A note on surfaces with large systoles

Yifei Cai

For every sufficiently large genus g, Cai constructs a closed hyperbolic surface with systole at least log g−12 log log g. The lower limit of the largest possible systole divided by log g is therefore at least one.

Sources for this record

What was already known

The best cited lower-limit coefficient for every genus was 2/9; coefficient one was known only along a sequence of genera.

AI involvement AI-led

Yifei Cai supplied the constant-twist pants-decomposition framework. He credits GPT-5.6 Sol with the first complete proof, then checked, simplified and reorganized it.

The model is expressly credited with the first complete proof; the author supplied the approach and subsequently checked and simplified it.

Importance Notable

Raises the every-genus asymptotic lower-limit coefficient from 2/9 to one.

Limitations

This improves the every-genus lower bound, not the sequence upper limit or the general asymptotic upper bound. Cai’s complete check is source-reported.

Technical verification Formal (human)

The author explicitly reports checking the full proof in the manuscript. No machine formalization or independent replay is documented.

Independent checking

author check of the complete GPT-developed proof, followed by simplification and reorganization

Checker
Yifei Cai
Scope
Theorem 1 every-sufficiently-large-genus systole bound
Basis
Reported by the linked checker
Evidence source

Human understanding Full

Cai gives and simplifies the central geometric coding, probability, and local-lemma mechanism; no central unexplained step is reported.

Correction and publication history